1. Field of the Description
The present description relates, in general, to three dimensional (3D) projection and display technology including 3D glasses or stereo glasses worn by viewers to perceive 3D imagery, and, more particularly, to 3D stereo display systems that are adapted for creating 3D effects or imagery with 3D content or media but without the need for conventional 3D projectors.
2. Relevant Background
Recently, there has been an increased interest in providing movies and other image-based content to viewers in 3D form, and there has been significant research in the past on technologies to produce 3D imagery. Most 3D technologies require the viewers to wear 3D glasses (or other headgear or other filters, which will be labeled “3D glasses” herein) such that left eye images are received by their left eye and right eye images are received by their right eyes. The combination of these right and left eye images is perceived by the viewers as 3D images or imagery (or stereo images).
Polarization and wavelength multiplex visualization (“WMV”) are two main types of 3D technologies that are in widespread use in cinema applications and in other entertainment venues including amusement or theme parks (e.g., in 3D rides, 3D displays, and other park attractions). In each of these 3D technologies or systems, the displays or projection systems have relied upon or targeted raster-based displays such as video projection, film, displays, and the like.
With polarized technology, the viewer wears low-cost eyeglasses that contain a pair of different polarizing filters. Each of the viewer's eyes sees a different image (right eye image and left eye image that were ultimately provided by cameras spaced apart the intraocular distance) because the filters pass only light having a particular polarization (i.e., matching the eyeglass filter) and block the light polarized differently (e.g., in the other polarization direction). Polarized technologies (linear and/or circular) are used to produce a 3D effect by projecting or displaying the same scene for viewing by both eyes, with the scene being depicted from slightly different offsets to create the necessary parallax to provide a 3D image. Use of this technology has the advantages of low cost glasses but is inefficient with light causing loss of brightness and requires a silvered screen to maintain polarization.
Due to these and other disadvantages with such 3D technologies, there has been increased interest in the use of wavelength multiplex visualization (also known as interference filters or comb filters and generally labeled “WMV” or “WMV technology” herein). WMV technology is based on a system of color. The specific color frequencies (e.g., left-eye RGB frequencies and right-eye RGB frequencies) utilized in each technology (or by each company's WMV products) are typically based on the specific delivery system and other parameters and company-specific goals.
Presently, there are at least two types of WMV technology used to provide 3D displays. In the first exemplary type of WMV technology-based 3D systems (e.g., Dolby 3D systems provided by Dolby Laboratories, Inc. or other WMV-based systems provided by other developers/distributors), a single projector is used that can project both left and right eye images using an alternate color wheel placed in the projector. The color wheel contains one more set of red, green, and blue filters in addition to the red, green, and blue filters found on a typical color wheel. The additional sets of three filters are able to produce the same color gamut as the original three filters but transmit light at different wavelengths. 3D glasses with complimentary dichroic filters in the lenses are worn by a viewer that filter out either one or the other set of the three light wavelengths. In this way one projector can display the left and right stereoscopic images simultaneously, e.g., by a stereoscopic projection process that is labeled herein as a first type of wavelength multiplex visualization or WMV (or is categorized as one form of wavelength multiplex visualization that may also be considered a narrowband-based WMV or a WMV implementing one or more narrowband source of illuminating light paired with 3D stereo glasses worn by a viewer to properly filter light from these sources).
A second exemplary type of WMV-based 3D system (e.g., a Christie 6P system available from Christie Digital Systems USA, Inc. or another designer/distributor of this second type of WMV) is built on a fiber-coupled, 6-primary projection system architecture rather than filtered or polarized broad-spectrum white light. In some systems using this second type of WMV, 6-Primary (“6P”) laser projectors employ two sets of red, green, and blue (RGB) laser lights, with one set being for the left eye and one, with slightly different wavelengths, for the right eye, which is why this second type of WMV-based 3D system is considered to employ or provide wavelength multiplex visualization. The viewer wears 3D glasses in these systems that filter out the different wavelengths and direct the light to the intended eye. This second type of WMV may be thought of as primary or colored laser projector-based WMV. There are a number of advantages associated with these systems including: effectiveness with light as almost 90 percent of the light from the projector makes it to the viewer's eye; does not require a silvered screen and can be both rear and front projected on nearly any surface; can be viewed from multiple points of view with no hot spot and has uniform brightness without regard to a viewer's point of view; can be used in applications where a viewer may tilt or move their head; and has a broad color gamut. As with the first type of WMV system, the stereo glasses for this second type of WMV system are expensive, and the light module and other projection components are also relatively expensive.
An ongoing challenge for many applications is how to integrate 3D projection or display systems in larger facilities rather than in the more contained theater setting. For example, many amusement parks include 3D theaters with long queues and 3D ride systems that now utilize wavelength multiplex visualization (“WMV”) technology such that visitors (or “viewers”) are now wearing stereo glasses adapted for use with such technologies rather than polarized glasses. These projection systems work through the realization that all humans see all colors using only the three color sensors in the eye for red, green, and blue. All other colors are synthesized by humans from mixtures of these three fundamental colors. As discussed above, for example, the first type of WMV system functions by splitting the red, green, and blue images to be displayed/projected into two narrow wavelength bands (e.g., Red1, Green1, and Blue2 or RGB1 and Red2, Green2, and Blue2 or RGB2). Then, for a left stereo image, the projector (or projectors if two are used) may project light with the wavelength bands for RGB1 and, for a right stereo image, the projector may project light with the wavelength bands for RGB2. The color separation is done with very narrowband color filters or lenses provided in the stereo glasses (e.g., with three filters overlaid for each of the viewer's eyes) such that the lens over the left eye only passes the RGB1 light or images while the lens over the right eye only passes the RGB2 light or images.
Projectors for systems employing wavelength multiplex visualization, which in combination may be considered conventional WMV projectors (or simply WMV projectors), narrowband multiplexing projectors, and the like, are expensive such that their use is generally limited to large-scale theatrical experiences. However, in amusement park rides and some theater settings, the viewers may be offered and be wearing the 3D stereo glasses designed for these systems outside of the theater or projection space. For example, a 3D-based ride may include one or more theater-type portions where a WMV projector(s) is used to project 3D images viewable by the ride participants. However, the ride participants will be wearing the 3D stereo glasses in other portions of the ride, which may be 50 to 90 percent of the length of the ride, where there is no 3D imagery being projected. One solution would be to provide the WMV projectors along the entire length of the ride, but this solution is typically discarded as being prohibitively expensive.
Hence, there remains a need for display systems and methods for providing 3D imagery to viewers such as in locations or spaces inside, nearby, and even outside of a conventional 3D theater setting (e.g., in the queue to or from the theater) and inside or even outside of portions of a ride configured for 3D projection. There is also a desire in some cases to provide 3D imagery and effects with higher brightness and/or in higher ambient light settings (e.g., not just in ideal low-light theater-type viewing environments).